Several chemotherapy agents with proven utility, e.g., anthracyclines, bleomycins, and noble metal derivatives, are being studied. The detoxification mechanisms, modification of cellular response by biochemical manipulation of intracellular redox status, and oxygen metabolism, in sensitive and resistant cells are of interest. Deleterious species produced by the antineoplastic drugs, and cellular response to these species, as well as thiol compounds, and their metabolic interactions with the drugs, and labile species produced by the drugs are being examined. It has been demonstrated that depletion of cellular glutathione (GSH) by inhibitors of GSH synthesis sensitize cells to adriamycin and bleomycin while GSH elevation provides protection. These studies will provide a better understanding of the mechanisms of drug action.